Just to gross everyone out, my Pioneer chainsaw engines with re-drives (that allow the engines to turn up over 8500 rpms) can see well over 450 degrees head temps during climb. I saw 475 on a few occasions! Since there was nothing I could do to reduce them - as I was already running fairly rich - I opted to remove the gauges so I wouldn't have to be reminded all the time. After hundreds and hundreds and hundreds of hours operations, I never had a piston seizure or failure, or any other damage to a piston. In fact, the only failures were one cracked head in an almost new engine, and one failed crankshaft bearing from spinning in the crankcase and overheating probably caused by my over tightening the belts. That was on my first set of engines with a little over 200 hours on them. It turned out 200 hours is about all the little engines (with the reduction units) would last flying an Ultralight and not cutting trees.

It's pretty hard to hurt a 185. Just tune for a bit rich after finding peak rpm's, and forgetabout it.

Chappy

I'm afraid I was a bit too flippant in my last remark. What I should have said is always tune to a bit on the rich side of peak rpm, and keep it set like that. If you do, I doubt you can hurt a 185 even if you don't monitor head temps. Not that I'm necessarily recommending that.